Interest-computing machine.



J. A. GASHBL. INTEREST COMPUTING MACHINE. APPLIOATION PIL'ED MAYZ, 1912yPatented Jan. 13, 1914,

2 SHEETS-SHEET l.

lill-1:21

IETEREST COMPUTING MACHINE.

IOATIR FILED MYZ, 1912.

Patented Jan 13, 1914.

2 BHEETS-BHEET 2.

ma MW M JOHN A. CASHEL, OF WORTHINGTON, MINNESOTA.

INTEREST-COMPTING MACHINE.

Specicatlon of Letters Patent.

Patented J an. 13, 1914.

Application filed May 2, 1912. Serial No. 694,613.

To all 'whom it may concern.'

Be it vknown that I, JOHN A. CAsHEL, a citizen of the United States,residing at lVorthington, in the county of Nobles and State ofhfli'nnesota, have invented certain new and useful Improvements inInterest- ComputingMachines, of which the following is a specification.

My invention relatesto computing machines, and particularly to thosewhich are used in the calculation or computation of interest, annuities,etc.

The main object of my invention is to provide `a computing machine ofsimple construction, by which interest upon different amounts vatdifferent rates may be quickly and accurately determined.

AI further object of the invention is to provide a machine of thischaracter in which a plurality of sets of related calculating tables areso arranged 4as to permit of adjustment within a suitable casing orcarrier to a position where they may be exposed to View, so that theoperator may move to proper position the table which he desires to use,while the others remain concealed in order to prevent confusion.

The nature and scope of my invention will be more fully understood fromthe following description, taken in connection with the accompanyingrdrawings, in whichl`igure 1 is a front elevation of a com puting machineembodying my invention; Fig. 2 'is an end elevation of the same; Fig. 3`is a vertical section on the line 3 3 of Fig. l; Fig. 4 is afragmentary sectional View of the right hand portion of the machine,showing the manner of mounting the interest rolls and the mechanism forrotating them; Fig. 5 is ,a detail sectional view of the time indicatorshown at the lefthand side of Fig. l; Fig. 6 is an enlarged perspectiveview of one of the finders; and Fig. 7 is a side elevation of one of theinterest-table rolls.

My interest-computing machine com prises a plurality of interest tableprisms or cylinders 1, having pivot pins 2, upon either end journaled indisks 4, carried by a central shaft 5, which is journaled in the endwalls of a casing 6. One end of the shaft is provided with a hand-wheel.7, by which the disks may be rotated, and the pivot-pins 2' carrypinions 9, which intermesh, so that a gear-wheel l2, normallyspring-pressed outwardly, may be pushed" into mesh with any adjacent`pinion when the entire series of prisms may be rotated axially by meansof the thumb-piece 14. The prisms or cylinders 1, thus have a planetarymovement,- that is to say, each is rotatable upon its own axis andbodily around the common central axis.

There are vpreferably .thirty-one prisms, one 'for each day of themonth, and each prism is provided with a plurality of faces carryingrespectivel series of gures indicating the interest or a certain numberof days for varying amounts. In Fig. 7, I have shown three faces of ahexagonal prism showing the interestfor twenty-five days at 4, 5, and 6per cent., respectively, upon amounts ranging from one hundred to ninehundred dollars. If desired, the rate per day for each amount may alsobe indicated in each space.

Above the skeleton day-cylinder above described, I may provide acorresponding skeleton cylinder having twelve interestbearing prisms forthe different months.v

The manner of mounting and operating these prisms is exactly similar tothat previously described in regard to the day cylinder, and I haveindicated the corresponding parts by the same reference numerals primed.A third multiple-prism cylinder to indicate the interest for a series ofyears may be placed above the monthly cylinder if desired.

The method of operating the portion of my machine above described forthe purpose of determining the interest for any amount will now beunderstood.

To find the amount for any number of days, the skeleton cylinder isfirst turned by means of the hand-wheel 7, until the proper day-prism isin alinement with the sightslot 15, extending across the front of thecasing, which is indicated by the pointer 17, standing opposite thecorresponding numeral on the face of the hand-Wheel 7. The cylinder isheld in any set positionby the dog 37, which rides over the toothedlocking wheel 36, The thumb-knob14 is then pushed inwardly until thespur-gear 12 is in mesh with the adjacent pinion 9, after which theseries of prisms may be rotated in unison about their axes, until theface bearing the series of interest computations for the desired .rateper cent. is opposite the sight-slot.l Extendinv longitudinally of theslot is a series of numbers, from one hundred to nine hundred, whichindicate the principal amounts corresponding with the adjacent interestcomputations. If desired, an indicator 20, having a magnifying lens 21,shown in detail in Fig. 6, may be mounted upon a guide-rod 23, andadapted to be slid over the res which are to be read. To furtherfacllitate the rzpid calculation of interest between certain ates, Iprovide a coplerating set of disks bearin upon their peri eries numberscorrespon ing respective y to the number of days lin a year and to thenumber of months, with subdivisions for the days of each month. Thesetwo disks 25, 26, are mounted upon the axle 28, the former loose thereonand the latter splined thereto. The loose disk 25 carries upon its perihery the 365 subdivisions, and is normal y in zero position, beingreturned after each operation by -means of a torsional spring 29.

The complete operation of m machine will be clear from the foregoingescription.

Let it be desired to determine the interest upon five hundred dollars atfive per cent., from March 14th until April 8th. The disk 26 is firstrotated by means of the thumbknob 30, until the date March 14th appearsin the sight-slot or window 32; then.- by pressing inwardly upon theknob, the notches or serratio 33, upon the adjacent edges of thediskslllsii and 26, are engaged. Now upon turning the\locked disks untilthe date April 8th, appears behind window 32,

the numeral 25, indicating the number of days between the two dates,will appear at the window upon the disk 25. As soon as pressure upon theknob 30 is released, the spring-operated disk 25 will be disengaged fromthe disk 26 and will return to zero position,l suitable stops 3 4 beingprovided to limit the movement. lslaving thus de-- termined the numberof days between the required dates, the main skeleton cylinder isrotated by means of the wheel 7 until the 25th day prism is opposite thesight-slot 15. After rotating the prisms upon their axes by means of thegear 12, as previously described, until the 5 per'ce'nt. face is visiblein the slot,l5, the indicator 2Q is; slid along the lr'odf23 until itisopposite'the sum `500 and the adjacent iiiterest'amofunt may then beread directly as $1.74. y These manipulations can be made very rapidland the simplicity of the machine Will e appreciated by bankers andothers who are required to determine uickly and in rapid succession theinterest etween certain dates upon varying amounts. at different rates.

I have described in detail the specific consfruction illustrated in theaccompanying drawings, for the purpose of disclosing an embodiment of myinvention, but I am aware that various changes may be made thereinwithout departingl from the scope of m claims or the spirit of myinvention.

1. In an interest-computing machine, comprising a revoluble disk havingupon its periphery a series of numerals arranged in arithmeticalprogression from unity upward, a spring normally causing said dlsk toassume a zero osition when unrestrained, a second revoluble disk coaxialwith said first disk and having upon its eriphery successive series ofnumerals indicating the days of each month, means for rotatin saidsecond disk independently ofthe rst-named disk, means for permittin onedisk to be moved toward the other dis and means for causing a lockingengagement therebetween, said spring operating to release said enagement when the parts are unrestrained, t ereby permitting thefirst-named disk to return to zero position.

2. An interest-computin machine comprising a casing having a sight-slottherein, a revoluble frame journaled in said casing, an annular seriesof revoluble cylinders journaled in said frame and rovided withintermeshing pinions, each o said c linders having inscribed thereon aplura ity of series of numerals indicating amounts of interest on sumsvarying progressively, each series being at a different rate, and theinterest amounts upon adjacent cylinders differingby 4a unit period. oftime, and a spurgear slidably mounted in thevcasing and normally out ofengagement with said pinions, 'but adapted to be moved into mesh withany adjacent pinion of the series, whereby the desired series of numbersmay he brought beneath said sight-slot.

Y. n .testimony whereof I ailix my signature inpresence of twowltnesses.

y JoHN A. CAsHEL. Witnesses:

HENRY NYs'rRoM,

ERNEST THOMPSON.

O opiel of thin patent may be obtained for ve cents each, 'by addressingthe Commissioner of Patents, Washington, D. C.

